Krishnacharya G. Akamanchi

Aryl-Free Radical-Mediated Oxidative Arylation of Naphthoquinones Using o-Iodoxybenzoic Acid and Phenylhydrazines and Its Application toward the Synthesis of Benzocarbazoledione

Oxidative arylation of naphthoquinones has been developed through combination of o-iodoxybenzoic acid with arylhydrazines under mild conditions at open atmosphere. Arylated naphthoquinones with different electronic properties were obtained in moderate to good yields. The postulated radical mediated mechanism is supported by radical trapping experiments. Developed protocol for direct arylation of naphthoquinones has been extended toward short, high yielding, and an effective synthesis of antitumor-antibiotic precursor such as benzocarbazoledione.

Sulfated tungstate: an efficient catalyst for the Ritter reaction

The use of sulfated tungstate as an efficient and reusable catalyst for the preparation of amides from alcohols and nitrilesvia the Ritter reaction pathway is discussed. The reaction proceeds under solvent free conditions.

Deoximation using Dess-Martin periodinane: Regeneration of ketones from ketoximes

Abstract The Dess-Martin Periodinane (DMP), [1,1,1-triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one], regenerates ketones from the corresponding ketoximes rapidly at room temperature in very high yields.

Sulfated tungstate: a highly efficient catalyst for transamidation of carboxamides with amines

An environmentally benign protocol for the transamidation of carboxamides with amines using sulfated tungstate, as a heterogeneous catalyst, has been developed. The method has been successfully applied to the synthesis of a wide range of aromatic and aliphatic amides and phthalimides. Efficient transformation, mild reaction conditions, easy product isolation and the potential reusability of the catalyst are attractive features.

Thionyl Chloride-Benzotriazole: An Efficient System For Transformation Of Aldoximes to Nitriles

Abstract Dehydration of aromatic as well as aliphatic aldoximes using thionyl chloride-benzotriazole combination in dry DCM proceeds smoothly at room temperature to give the corresponding nitriles in high yields (>90%) in shorter time(~20min).

Oleic acid based heterolipid synthesis, characterization and application in self-microemulsifying drug delivery system

There is increasing demand for lipids owing to their use in formulating lipid based drug delivery systems of poorly soluble drugs. The present work discusses the synthesis, characterization of oleic acid based heterolipid and its use as oil in the development of self-microemulsifying drug delivery system (SMEDDS) for parenteral delivery. Synthesis was carried out by Michael addition of tert-butyl acrylate to 3-amino-1-propanol to obtain di-tert-butyl aminopropanol derivative. Reaction of this di-tert-butyl aminopropanol derivative with oleoyl chloride using p-dimethylaminopyridine as a coupling agent gave the desired heterolipid. It was characterized by (1)H NMR, (13)C NMR and MS to confirm the structure. It did not exhibit any measurable cytotoxicity, even up to 80μg/ml concentration. Application in parenteral drug delivery was explored using furosemide (FUR), a BCS class IV drug, as a model. FUR showed three times greater solubility in the heterolipid as compared to oleic acid. SMEDDSs were developed using heterolipid as oily phase, Solutol HS 15(®) as surfactant and ethanol as a co-surfactant. Developed SMEDDS could form spontaneous microemulsion on addition to various aqueous phases with mean globule size <70nm without any phase separation or drug precipitation even after 24h, and exhibited negligible hemolytic potential.

Oxidative Conversion of α,α-Disubstituted Acetamides to Corresponding One-Carbon-Shorter Ketones Using Hypervalent Iodine (λ5) Reagents in Combination with Tetraethylammonium Bromide

Alpha,alpha-disubstituted acetamides undergo oxidative dehomologation to give one-carbon-shorter ketones when reacted with a hypervalent iodine (lambda(5)) reagent in combination with tetraethylammonium bromide (TEAB) in various solvents. In further studies, one such combination of a hypervalent iodine (lambda(5)) reagent, o-iodoxybenzoic acid, and TEAB has been established as a new, mild, efficient, and general method for the transformation.

Aluminium isopropoxide - TFA, a modified catalyst for highly accelerated meerwein - ponndorf - verley (MPV) reduction

Abstract Aldehydes and ketones have been reduced very rapidly in good yields at room temperature by addition of trifluoroacetic acid (TFA) to aluminium isopropoxide (AIP) in MPC reduction.

Dendrimers – from organic synthesis to pharmaceutical applications: an update

Abstract Dendrimers are a relatively new class of monodisperse polymers, which have tree-like spherical structures with well-defined sizes and shapes. Their unique structure has a significant impact on their physical and chemical properties. Research on dendrimers is of significant interest to scientists from all areas and their utility in various scientific fields, including pharmaceuticals, is expanding. The present review is comprehensive and covers different aspects of dendrimers viz. (1) synthesis, (2) properties and (3) pharmaceutical applications. The emphasis is on their applications as well as the current ongoing research status for drug targeting.

A novel biocompatible bicephalous dianionic surfactant from oleic acid for solid lipid nanoparticles

New biocompatible bicephalous dianionic surfactant with low CMC value was successfully synthesized and its efficacy in pharmaceutical drug delivery system was explored by preparing solid lipid nanoparticles (SLNs) of ketoconazole, a BCS class II drug. Oleic acid based dianionic surfactant was synthesized by attachment of oleic acid through ester linkage, to a bidentate head component, prepared by 1,4-addition of propanolamine and tert-butyl acrylate, followed by hydrolysis and neutralization with sodium bicarbonate. Its critical micelle concentration (CMC), hydrophilic-lipophilic balance and logPoctanol/water were found to be 1.6mM/L, 34.68 and -2.96, respectively. Cytotoxicity study, conducted using sulforhodamine B assay, showed LC50, GI50 and TGI values>80 μg/ml indicating its biocompatibility. It was found to be non-irritant by in vivo skin irritation study. The particle size, polydispersity index, and zeta potential of the optimized formulation were 98.2±1.74 nm, 0.462±0.016, and -49.6 mV, respectively. Further, the SLNs were characterized by scanning electron microscopy, differential scanning calorimetry and X-ray diffraction studies. Drug entrapment efficiency was found to be 87.42±0.31%, and the SLNs exhibited good stability over a period of 3 months. The current investigations, therefore, report the successful development of systematically optimized SLNs of ketoconazole.